Silicon enhances drought tolerance in tomato plants

Drought stress is one of the major factors limiting crop productivity in water-scarce regions. Early detection and mitigation of drought effects in tomato plants are essential for optimizing irrigation and maintaining fruit quality. This study investigated the effects of silicon (Si) supplementation and drought stress on the physiological and biochemical responses of tomato plants. A completely randomized factorial design was established with four Si concentrations (0, 0.75, 1.5, and 3 mM) and three levels of water stress (control at 80 %, moderate stress at 60 %, and severe stress at 40 % of field capacity [FC]). Treatments were analyzed in triplicate, and the variables evaluated were fresh and dry weight, proline content, antioxidant enzyme activity, hydrogen peroxide (H2O2) accumulation, and malondialdehyde (MDA) concentration. The results indicated that 0.75 mM Si under moderate drought significantly increased superoxide dismutase (SOD) activity. However, increasing drought intensity resulted in higher H2O2 accumulation across most Si treatments. The highest MDA concentration was also recorded in plants receiving 0.75 mM Si under moderate stress. Overall, Si application modulated the physiological and biochemical responses of tomato plants to water deficit, suggesting its potential to alleviate the adverse effects of drought stress on plant growth and metabolism.